Toward the unity of pathological and exertional fatigue: A predictive processing model

Area of Science:

• Clinical Neurosciences
• Cognitive Science
• Psychology

Background:

• Fatigue is a common symptom in health and disease, traditionally viewed as distinct pathological and transient forms.
• Existing research separates the study of chronic and exertional fatigue, hindering a unified understanding.
• Clinical neurosciences are exploring predictive processing frameworks for pathological fatigue.

Purpose of the Study:

• To extend the metacognitive theory of dyshomeostasis to explain the development of exertional fatigue.
• To propose a common mechanistic foundation for both pathological and transient fatigue.
• To integrate disparate research fields studying fatigue.

Main Methods:

• Drawing on the metacognitive theory of dyshomeostasis.
• Extending hierarchical predictive processing frameworks.
• Describing the dynamic computations underlying fatigue development during exertion.

Main Results:

• Pathological fatigue arises from metacognitive detection of persistent prediction errors, signaling low confidence in internal models.
• Exertional fatigue is also associated with increasing interoceptive prediction error.
• A proposed common foundation for both fatigue types is the loss of certainty in control predictions due to sustained prediction errors.

Conclusions:

• The metacognitive theory of dyshomeostasis provides a unified framework for understanding fatigue.
• Both pathological and exertional fatigue may share a common origin in prediction error signaling.
• This unified perspective can bridge research gaps in the study of fatigue.